WebSVN – HelenOS – Diff – /branches/dd/uspace/srv/fs/fat/fat_ops.c

  * @file    fat_ops.c
  * @brief   Implementation of VFS operations for the FAT file system server.
  */
 #include "fat.h"
+#include "fat_dentry.h"
+#include "fat_fat.h"
 #include "../../vfs/vfs.h"
 #include <libfs.h>
+#include <libblock.h>
 #include <ipc/ipc.h>
+#include <ipc/services.h>
+#include <ipc/devmap.h>
 #include <async.h>
 #include <errno.h>
 #include <string.h>
 #include <byteorder.h>
 #include <libadt/hash_table.h>
 #include <libadt/list.h>
 #include <assert.h>
 #include <futex.h>
-#define BS_BLOCK        0
+#include <sys/mman.h>
+#include <align.h>
 /** Futex protecting the list of cached free FAT nodes. */
 static futex_t ffn_futex = FUTEX_INITIALIZER;
 /** List of cached free FAT nodes. */
 static LIST_INITIALIZE(ffn_head);
-#define FAT_NAME_LEN        8
-#define FAT_EXT_LEN     3
-#define FAT_PAD         ' '
-#define FAT_DENTRY_UNUSED   0x00
-#define FAT_DENTRY_E5_ESC   0x05
-#define FAT_DENTRY_DOT      0x2e
-#define FAT_DENTRY_ERASED   0xe5
-static void dentry_name_canonify(fat_dentry_t *d, char *buf)
-{
-    int i;
-    for (i = 0; i < FAT_NAME_LEN; i++) {
-        if (d->name[i] == FAT_PAD) {
-            buf++;
-            break;
-        }
-        if (d->name[i] == FAT_DENTRY_E5_ESC)
-            *buf++ = 0xe5;
-        else
-            *buf++ = d->name[i];
-    }
-    if (d->ext[0] != FAT_PAD)
-        *buf++ = '.';
-    for (i = 0; i < FAT_EXT_LEN; i++) {
-        if (d->ext[i] == FAT_PAD) {
-            *buf = '\0';
-            return;
-        }
-        if (d->ext[i] == FAT_DENTRY_E5_ESC)
-            *buf++ = 0xe5;
-        else
-            *buf++ = d->ext[i];
-    }
-}
-/* TODO move somewhere else */
-typedef struct {
-    void *data;
-} block_t;
-static block_t *block_get(dev_handle_t dev_handle, off_t offset)
-{
-    return NULL;    /* TODO */
-}
-static void block_put(block_t *block)
-{
-    /* TODO */
-}
-#define FAT_BS(b)       ((fat_bs_t *)((b)->data))
-#define FAT_CLST_RES0   0x0000
-#define FAT_CLST_RES1   0x0001  /* internally used to mark root directory */
-#define FAT_CLST_FIRST  0x0002
-#define FAT_CLST_BAD    0xfff7
-#define FAT_CLST_LAST1  0xfff8
-#define FAT_CLST_LAST8  0xffff
-#define fat_block_get(np, off) \
-    _fat_block_get((np)->idx->dev_handle, (np)->firstc, (off))
-static block_t *
-_fat_block_get(dev_handle_t dev_handle, fat_cluster_t firstc, off_t offset)
-{
-    block_t *bb;
-    block_t *b;
-    unsigned bps;
-    unsigned spc;
-    unsigned rscnt;     /* block address of the first FAT */
-    unsigned fatcnt;
-    unsigned rde;
-    unsigned rds;       /* root directory size */
-    unsigned sf;
-    unsigned ssa;       /* size of the system area */
-    unsigned clusters;
-    fat_cluster_t clst = firstc;
-    unsigned i;
-    bb = block_get(dev_handle, BS_BLOCK);
-    bps = uint16_t_le2host(FAT_BS(bb)->bps);
-    spc = FAT_BS(bb)->spc;
-    rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);
-    fatcnt = FAT_BS(bb)->fatcnt;
-    rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);
-    sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat);
-    block_put(bb);
-    rds = (sizeof(fat_dentry_t) * rde) / bps;
-    rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);
-    ssa = rscnt + fatcnt * sf + rds;
-    if (firstc == FAT_CLST_RES1) {
-        /* root directory special case */
-        assert(offset < rds);
-        b = block_get(dev_handle, rscnt + fatcnt * sf + offset);
-        return b;
-    }
-    clusters = offset / spc;
-    for (i = 0; i < clusters; i++) {
-        unsigned fsec;  /* sector offset relative to FAT1 */
-        unsigned fidx;  /* FAT1 entry index */
-        assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);
-        fsec = (clst * sizeof(fat_cluster_t)) / bps;
-        fidx = clst % (bps / sizeof(fat_cluster_t));
-        /* read FAT1 */
-        b = block_get(dev_handle, rscnt + fsec);
-        clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
-        assert(clst != FAT_CLST_BAD);
-        assert(clst < FAT_CLST_LAST1);
-        block_put(b);
-    }
-    b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +
-        offset % spc);
-    return b;
-}
 static void fat_node_initialize(fat_node_t *node)
+{
     futex_initialize(&node->lock, 1);
     node->idx = NULL;
     node->type = 0;
     node->lnkcnt = 0;
     node->refcnt = 0;
     node->dirty = false;
+}
-static uint16_t fat_bps_get(dev_handle_t dev_handle)
+static void fat_node_sync(fat_node_t *node)
+{
-    block_t *bb;
+    block_t *b;
+    fat_bs_t *bs;
+    fat_dentry_t *d;
     uint16_t bps;
+    unsigned dps;
-    bb = block_get(dev_handle, BS_BLOCK);
-    assert(bb != NULL);
+    assert(node->dirty);
-    bps = uint16_t_le2host(FAT_BS(bb)->bps);
-    block_put(bb);
+    bs = block_bb_get(node->idx->dev_handle);
-    return bps;
+    bps = uint16_t_le2host(bs->bps);
+    dps = bps / sizeof(fat_dentry_t);
-}
+    /* Read the block that contains the dentry of interest. */
+    b = _fat_block_get(bs, node->idx->dev_handle, node->idx->pfc,
+        (node->idx->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
-typedef enum {
-    FAT_DENTRY_SKIP,
-    FAT_DENTRY_LAST,
-    FAT_DENTRY_VALID
-} fat_dentry_clsf_t;
+    d = ((fat_dentry_t *)b->data) + (node->idx->pdi % dps);
-static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d)
+    d->firstc = host2uint16_t_le(node->firstc);
-{
-    if (d->attr & FAT_ATTR_VOLLABEL) {
-        /* volume label entry */
-        return FAT_DENTRY_SKIP;
-    }
-    if (d->name[0] == FAT_DENTRY_ERASED) {
+    if (node->type == FAT_FILE) {
-        /* not-currently-used entry */
+        d->size = host2uint32_t_le(node->size);
-        return FAT_DENTRY_SKIP;
-    }
-    if (d->name[0] == FAT_DENTRY_UNUSED) {
-        /* never used entry */
-        return FAT_DENTRY_LAST;
-    }
-    if (d->name[0] == FAT_DENTRY_DOT) {
+    } else if (node->type == FAT_DIRECTORY) {
-        /*
-         * Most likely '.' or '..'.
-         * It cannot occur in a regular file name.
-         */
-        return FAT_DENTRY_SKIP;
+        d->attr = FAT_ATTR_SUBDIR;
+    }
+    /* TODO: update other fields? (e.g time fields) */
+    b->dirty = true;        /* need to sync block */
-    return FAT_DENTRY_VALID;
+    block_put(b);
+}
-static void fat_node_sync(fat_node_t *node)
+static fat_node_t *fat_node_get_new(void)
+{
-    /* TODO */
-}
-/** Internal version of fat_node_get().
- *
- * @param idxp      Locked index structure.
- */
-static void *fat_node_get_core(fat_idx_t *idxp)
-{
-    block_t *b;
-    fat_dentry_t *d;
     fat_node_t *nodep;
-    unsigned bps;
-    unsigned dps;
-    if (idxp->nodep) {
-        /*
-         * We are lucky.
-         * The node is already instantiated in memory.
-         */
-        futex_down(&idxp->nodep->lock);
-        if (!idxp->nodep->refcnt++)
-            list_remove(&nodep->ffn_link);
-        futex_up(&idxp->nodep->lock);
-        return idxp->nodep;
-    }
-    /*
-     * We must instantiate the node from the file system.
-     */
-    assert(idxp->pfc);
     futex_down(&ffn_futex);
     if (!list_empty(&ffn_head)) {
         /* Try to use a cached free node structure. */
         fat_idx_t *idxp_tmp;
         nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
         if (!nodep)
             return NULL;
+    }
     fat_node_initialize(nodep);
+    return nodep;
+}
+/** Internal version of fat_node_get().
+ *
+ * @param idxp      Locked index structure.
+ */
+static void *fat_node_get_core(fat_idx_t *idxp)
+{
+    block_t *b;
+    fat_bs_t *bs;
+    fat_dentry_t *d;
+    fat_node_t *nodep = NULL;
+    unsigned bps;
+    unsigned spc;
+    unsigned dps;
+    if (idxp->nodep) {
+        /*
+         * We are lucky.
+         * The node is already instantiated in memory.
+         */
+        futex_down(&idxp->nodep->lock);
+        if (!idxp->nodep->refcnt++)
+            list_remove(&idxp->nodep->ffn_link);
+        futex_up(&idxp->nodep->lock);
+        return idxp->nodep;
+    }
+    /*
+     * We must instantiate the node from the file system.
+     */
+    assert(idxp->pfc);
+    nodep = fat_node_get_new();
+    if (!nodep)
+        return NULL;
-    bps = fat_bps_get(idxp->dev_handle);
+    bs = block_bb_get(idxp->dev_handle);
+    bps = uint16_t_le2host(bs->bps);
+    spc = bs->spc;
     dps = bps / sizeof(fat_dentry_t);
     /* Read the block that contains the dentry of interest. */
-    b = _fat_block_get(idxp->dev_handle, idxp->pfc,
+    b = _fat_block_get(bs, idxp->dev_handle, idxp->pfc,
-        (idxp->pdi * sizeof(fat_dentry_t)) / bps);
+        (idxp->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
     assert(b);
     d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);
     if (d->attr & FAT_ATTR_SUBDIR) {
         /*
          * The only directory which does not have this bit set is the
          * root directory itself. The root directory node is handled
          * and initialized elsewhere.
          */
         nodep->type = FAT_DIRECTORY;
+        /*
+         * Unfortunately, the 'size' field of the FAT dentry is not
+         * defined for the directory entry type. We must determine the
+         * size of the directory by walking the FAT.
+         */
+        nodep->size = bps * spc * fat_clusters_get(bs, idxp->dev_handle,
+            uint16_t_le2host(d->firstc));
     } else {
         nodep->type = FAT_FILE;
+        nodep->size = uint32_t_le2host(d->size);
+    }
     nodep->firstc = uint16_t_le2host(d->firstc);
-    nodep->size = uint32_t_le2host(d->size);
     nodep->lnkcnt = 1;
     nodep->refcnt = 1;
     block_put(b);
     idxp->nodep = nodep;
     return nodep;
+}
+/*
+ * Forward declarations of FAT libfs operations.
+ */
+static void *fat_node_get(dev_handle_t, fs_index_t);
+static void fat_node_put(void *);
+static void *fat_create_node(dev_handle_t, int);
+static int fat_destroy_node(void *);
+static int fat_link(void *, void *, const char *);
+static int fat_unlink(void *, void *);
+static void *fat_match(void *, const char *);
+static fs_index_t fat_index_get(void *);
+static size_t fat_size_get(void *);
+static unsigned fat_lnkcnt_get(void *);
+static bool fat_has_children(void *);
+static void *fat_root_get(dev_handle_t);
+static char fat_plb_get_char(unsigned);
+static bool fat_is_directory(void *);
+static bool fat_is_file(void *node);
+/*
+ * FAT libfs operations.
+ */
 /** Instantiate a FAT in-core node. */
-static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
+void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
+{
     void *node;
     fat_idx_t *idxp;
     idxp = fat_idx_get_by_index(dev_handle, index);
     node = fat_node_get_core(idxp);
     futex_up(&idxp->lock);
     return node;
+}
-static void fat_node_put(void *node)
+void fat_node_put(void *node)
+{
     fat_node_t *nodep = (fat_node_t *)node;
+    bool destroy = false;
     futex_down(&nodep->lock);
     if (!--nodep->refcnt) {
+        if (nodep->idx) {
-        futex_down(&ffn_futex);
+            futex_down(&ffn_futex);
-        list_append(&nodep->ffn_link, &ffn_head);
+            list_append(&nodep->ffn_link, &ffn_head);
-        futex_up(&ffn_futex);
+            futex_up(&ffn_futex);
+        } else {
+            /*
+             * The node does not have any index structure associated
+             * with itself. This can only mean that we are releasing
+             * the node after a failed attempt to allocate the index
+             * structure for it.
+             */
+            destroy = true;
+        }
+    }
     futex_up(&nodep->lock);
+    if (destroy)
+        free(node);
+}
-static void *fat_create(int flags)
+void *fat_create_node(dev_handle_t dev_handle, int flags)
+{
+    fat_idx_t *idxp;
+    fat_node_t *nodep;
+    fat_bs_t *bs;
+    fat_cluster_t mcl, lcl;
+    uint16_t bps;
+    int rc;
+    bs = block_bb_get(dev_handle);
+    bps = uint16_t_le2host(bs->bps);
+    if (flags & L_DIRECTORY) {
+        /* allocate a cluster */
+        rc = fat_alloc_clusters(bs, dev_handle, 1, &mcl, &lcl);
+        if (rc != EOK)
+            return NULL;
+    }
+    nodep = fat_node_get_new();
+    if (!nodep) {
+        fat_free_clusters(bs, dev_handle, mcl);
+        return NULL;
+    }
+    idxp = fat_idx_get_new(dev_handle);
+    if (!idxp) {
+        fat_free_clusters(bs, dev_handle, mcl);
+        fat_node_put(nodep);
+        return NULL;
+    }
+    /* idxp->lock held */
+    if (flags & L_DIRECTORY) {
+        int i;
+        block_t *b;
+        /*
+         * Populate the new cluster with unused dentries.
+         */
+        for (i = 0; i < bs->spc; i++) {
+            b = _fat_block_get(bs, dev_handle, mcl, i,
+                BLOCK_FLAGS_NOREAD);
+            /* mark all dentries as never-used */
+            memset(b->data, 0, bps);
+            b->dirty = false;
+            block_put(b);
+        }
+        nodep->type = FAT_DIRECTORY;
+        nodep->firstc = mcl;
+        nodep->size = bps * bs->spc;
+    } else {
+        nodep->type = FAT_FILE;
+        nodep->firstc = FAT_CLST_RES0;
+        nodep->size = 0;
+    }
-    return NULL;    /* not supported at the moment */
+    nodep->lnkcnt = 0;  /* not linked anywhere */
+    nodep->refcnt = 1;
+    nodep->dirty = true;
+    nodep->idx = idxp;
+    idxp->nodep = nodep;
+    futex_up(&idxp->lock);
+    return nodep;
+}
-static int fat_destroy(void *node)
+int fat_destroy_node(void *node)
+{
+    fat_node_t *nodep = (fat_node_t *)node;
+    fat_bs_t *bs;
+    /*
+     * The node is not reachable from the file system. This means that the
+     * link count should be zero and that the index structure cannot be
+     * found in the position hash. Obviously, we don't need to lock the node
+     * nor its index structure.
+     */
+    assert(nodep->lnkcnt == 0);
+    /*
+     * The node may not have any children.
+     */
+    assert(fat_has_children(node) == false);
+    bs = block_bb_get(nodep->idx->dev_handle);
+    if (nodep->firstc != FAT_CLST_RES0) {
+        assert(nodep->size);
-    return ENOTSUP; /* not supported at the moment */
+        /* Free all clusters allocated to the node. */
+        fat_free_clusters(bs, nodep->idx->dev_handle, nodep->firstc);
+    }
+    fat_idx_destroy(nodep->idx);
+    free(nodep);
+    return EOK;
+}
-static bool fat_link(void *prnt, void *chld, const char *name)
+int fat_link(void *prnt, void *chld, const char *name)
+{
+    fat_node_t *parentp = (fat_node_t *)prnt;
+    fat_node_t *childp = (fat_node_t *)chld;
+    fat_dentry_t *d;
+    fat_bs_t *bs;
+    block_t *b;
+    int i, j;
+    uint16_t bps;
+    unsigned dps;
+    unsigned blocks;
+    fat_cluster_t mcl, lcl;
+    int rc;
+    futex_down(&childp->lock);
+    if (childp->lnkcnt == 1) {
+        /*
-    return false;   /* not supported at the moment */
+         * On FAT, we don't support multiple hard links.
+         */
+        futex_up(&childp->lock);
+        return EMLINK;
+    }
+    assert(childp->lnkcnt == 0);
+    futex_up(&childp->lock);
+    if (!fat_dentry_name_verify(name)) {
+        /*
+         * Attempt to create unsupported name.
+         */
+        return ENOTSUP;
+    }
+    /*
+     * Get us an unused parent node's dentry or grow the parent and allocate
+     * a new one.
+     */
+    futex_down(&parentp->idx->lock);
+    bs = block_bb_get(parentp->idx->dev_handle);
+    bps = uint16_t_le2host(bs->bps);
+    dps = bps / sizeof(fat_dentry_t);
+    blocks = parentp->size / bps;
+    for (i = 0; i < blocks; i++) {
+        b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);
+        for (j = 0; j < dps; j++) {
+            d = ((fat_dentry_t *)b->data) + j;
+            switch (fat_classify_dentry(d)) {
+            case FAT_DENTRY_SKIP:
+            case FAT_DENTRY_VALID:
+                /* skipping used and meta entries */
+                continue;
+            case FAT_DENTRY_FREE:
+            case FAT_DENTRY_LAST:
+                /* found an empty slot */
+                goto hit;
+            }
+        }
+        block_put(b);
+    }
+    j = 0;
+    /*
+     * We need to grow the parent in order to create a new unused dentry.
+     */
+    if (parentp->idx->pfc == FAT_CLST_ROOT) {
+        /* Can't grow the root directory. */
+        futex_up(&parentp->idx->lock);
+        return ENOSPC;
+    }
+    rc = fat_alloc_clusters(bs, parentp->idx->dev_handle, 1, &mcl, &lcl);
+    if (rc != EOK) {
+        futex_up(&parentp->idx->lock);
+        return rc;
+    }
+    fat_append_clusters(bs, parentp, mcl);
+    b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NOREAD);
+    d = (fat_dentry_t *)b->data;
+    /*
+     * Clear all dentries in the block except for the first one (the first
+     * dentry will be cleared in the next step).
+     */
+    memset(d + 1, 0, bps - sizeof(fat_dentry_t));
+hit:
+    /*
+     * At this point we only establish the link between the parent and the
+     * child.  The dentry, except of the name and the extension, will remain
+     * uninitialized until the corresponding node is synced. Thus the valid
+     * dentry data is kept in the child node structure.
+     */
+    memset(d, 0, sizeof(fat_dentry_t));
+    fat_dentry_name_set(d, name);
+    b->dirty = true;        /* need to sync block */
+    block_put(b);
+    futex_up(&parentp->idx->lock);
+    futex_down(&childp->idx->lock);
+    /*
+     * If possible, create the Sub-directory Identifier Entry and the
+     * Sub-directory Parent Pointer Entry (i.e. "." and ".."). These entries
+     * are not mandatory according to Standard ECMA-107 and HelenOS VFS does
+     * not use them anyway, so this is rather a sign of our good will.
+     */
+    b = fat_block_get(bs, childp, 0, BLOCK_FLAGS_NONE);
+    d = (fat_dentry_t *)b->data;
+    if (fat_classify_dentry(d) == FAT_DENTRY_LAST ||
+        strcmp(d->name, FAT_NAME_DOT) == 0) {
+        memset(d, 0, sizeof(fat_dentry_t));
+        strcpy(d->name, FAT_NAME_DOT);
+        strcpy(d->ext, FAT_EXT_PAD);
+        d->attr = FAT_ATTR_SUBDIR;
+        d->firstc = host2uint16_t_le(childp->firstc);
+        /* TODO: initialize also the date/time members. */
+    }
+    d++;
+    if (fat_classify_dentry(d) == FAT_DENTRY_LAST ||
+        strcmp(d->name, FAT_NAME_DOT_DOT) == 0) {
+        memset(d, 0, sizeof(fat_dentry_t));
+        strcpy(d->name, FAT_NAME_DOT_DOT);
+        strcpy(d->ext, FAT_EXT_PAD);
+        d->attr = FAT_ATTR_SUBDIR;
+        d->firstc = (parentp->firstc == FAT_CLST_ROOT) ?
+            host2uint16_t_le(FAT_CLST_RES0) :
+            host2uint16_t_le(parentp->firstc);
+        /* TODO: initialize also the date/time members. */
+    }
+    b->dirty = true;        /* need to sync block */
+    block_put(b);
+    childp->idx->pfc = parentp->firstc;
+    childp->idx->pdi = i * dps + j;
+    futex_up(&childp->idx->lock);
+    futex_down(&childp->lock);
+    childp->lnkcnt = 1;
+    childp->dirty = true;       /* need to sync node */
+    futex_up(&childp->lock);
+    /*
+     * Hash in the index structure into the position hash.
+     */
+    fat_idx_hashin(childp->idx);
+    return EOK;
+}
-static int fat_unlink(void *prnt, void *chld)
+int fat_unlink(void *prnt, void *chld)
+{
+    fat_node_t *parentp = (fat_node_t *)prnt;
+    fat_node_t *childp = (fat_node_t *)chld;
+    fat_bs_t *bs;
+    fat_dentry_t *d;
+    uint16_t bps;
+    block_t *b;
+    futex_down(&parentp->lock);
+    futex_down(&childp->lock);
+    assert(childp->lnkcnt == 1);
+    futex_down(&childp->idx->lock);
+    bs = block_bb_get(childp->idx->dev_handle);
+    bps = uint16_t_le2host(bs->bps);
+    b = _fat_block_get(bs, childp->idx->dev_handle, childp->idx->pfc,
+        (childp->idx->pdi * sizeof(fat_dentry_t)) / bps,
+        BLOCK_FLAGS_NONE);
+    d = (fat_dentry_t *)b->data +
+        (childp->idx->pdi % (bps / sizeof(fat_dentry_t)));
+    /* mark the dentry as not-currently-used */
+    d->name[0] = FAT_DENTRY_ERASED;
-    return ENOTSUP; /* not supported at the moment */
+    b->dirty = true;        /* need to sync block */
+    block_put(b);
+    /* remove the index structure from the position hash */
+    fat_idx_hashout(childp->idx);
+    /* clear position information */
+    childp->idx->pfc = FAT_CLST_RES0;
+    childp->idx->pdi = 0;
+    futex_up(&childp->idx->lock);
+    childp->lnkcnt = 0;
+    childp->dirty = true;
+    futex_up(&childp->lock);
+    futex_up(&parentp->lock);
+    return EOK;
+}
-static void *fat_match(void *prnt, const char *component)
+void *fat_match(void *prnt, const char *component)
+{
+    fat_bs_t *bs;
     fat_node_t *parentp = (fat_node_t *)prnt;
     char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
     unsigned i, j;
     unsigned bps;       /* bytes per sector */
     unsigned dps;       /* dentries per sector */
     unsigned blocks;
     fat_dentry_t *d;
     block_t *b;
     futex_down(&parentp->idx->lock);
-    bps = fat_bps_get(parentp->idx->dev_handle);
+    bs = block_bb_get(parentp->idx->dev_handle);
+    bps = uint16_t_le2host(bs->bps);
     dps = bps / sizeof(fat_dentry_t);
-    blocks = parentp->size / bps + (parentp->size % bps != 0);
+    blocks = parentp->size / bps;
     for (i = 0; i < blocks; i++) {
-        unsigned dentries;
-        b = fat_block_get(parentp, i);
+        b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);
-        dentries = (i == blocks - 1) ?
-            parentp->size % sizeof(fat_dentry_t) :
-            dps;
-        for (j = 0; j < dentries; j++) {
+        for (j = 0; j < dps; j++) {
             d = ((fat_dentry_t *)b->data) + j;
             switch (fat_classify_dentry(d)) {
             case FAT_DENTRY_SKIP:
+            case FAT_DENTRY_FREE:
                 continue;
             case FAT_DENTRY_LAST:
                 block_put(b);
                 futex_up(&parentp->idx->lock);
                 return NULL;
             default:
             case FAT_DENTRY_VALID:
-                dentry_name_canonify(d, name);
+                fat_dentry_name_get(d, name);
                 break;
+            }
-            if (strcmp(name, component) == 0) {
+            if (fat_dentry_namecmp(name, component) == 0) {
                 /* hit */
                 void *node;
                 /*
                  * Assume tree hierarchy for locking.  We
                  * already have the parent and now we are going
                 return node;
+            }
+        }
         block_put(b);
+    }
     futex_up(&parentp->idx->lock);
     return NULL;
+}
-static fs_index_t fat_index_get(void *node)
+fs_index_t fat_index_get(void *node)
+{
     fat_node_t *fnodep = (fat_node_t *)node;
     if (!fnodep)
         return 0;
     return fnodep->idx->index;
+}
-static size_t fat_size_get(void *node)
+size_t fat_size_get(void *node)
+{
     return ((fat_node_t *)node)->size;
+}
-static unsigned fat_lnkcnt_get(void *node)
+unsigned fat_lnkcnt_get(void *node)
+{
     return ((fat_node_t *)node)->lnkcnt;
+}
-static bool fat_has_children(void *node)
+bool fat_has_children(void *node)
+{
+    fat_bs_t *bs;
     fat_node_t *nodep = (fat_node_t *)node;
     unsigned bps;
     unsigned dps;
     unsigned blocks;
     block_t *b;
     unsigned i, j;
     if (nodep->type != FAT_DIRECTORY)
         return false;
     futex_down(&nodep->idx->lock);
-    bps = fat_bps_get(nodep->idx->dev_handle);
+    bs = block_bb_get(nodep->idx->dev_handle);
+    bps = uint16_t_le2host(bs->bps);
     dps = bps / sizeof(fat_dentry_t);
-    blocks = nodep->size / bps + (nodep->size % bps != 0);
+    blocks = nodep->size / bps;
     for (i = 0; i < blocks; i++) {
-        unsigned dentries;
         fat_dentry_t *d;
-        b = fat_block_get(nodep, i);
+        b = fat_block_get(bs, nodep, i, BLOCK_FLAGS_NONE);
-        dentries = (i == blocks - 1) ?
-            nodep->size % sizeof(fat_dentry_t) :
-            dps;
-        for (j = 0; j < dentries; j++) {
+        for (j = 0; j < dps; j++) {
             d = ((fat_dentry_t *)b->data) + j;
             switch (fat_classify_dentry(d)) {
             case FAT_DENTRY_SKIP:
+            case FAT_DENTRY_FREE:
                 continue;
             case FAT_DENTRY_LAST:
                 block_put(b);
                 futex_up(&nodep->idx->lock);
                 return false;
     futex_up(&nodep->idx->lock);
     return false;
+}
-static void *fat_root_get(dev_handle_t dev_handle)
+void *fat_root_get(dev_handle_t dev_handle)
+{
-    return NULL;    /* TODO */
+    return fat_node_get(dev_handle, 0);
+}
-static char fat_plb_get_char(unsigned pos)
+char fat_plb_get_char(unsigned pos)
+{
     return fat_reg.plb_ro[pos % PLB_SIZE];
+}
-static bool fat_is_directory(void *node)
+bool fat_is_directory(void *node)
+{
     return ((fat_node_t *)node)->type == FAT_DIRECTORY;
+}
-static bool fat_is_file(void *node)
+bool fat_is_file(void *node)
+{
     return ((fat_node_t *)node)->type == FAT_FILE;
+}
 /** libfs operations */
 libfs_ops_t fat_libfs_ops = {
     .match = fat_match,
     .node_get = fat_node_get,
     .node_put = fat_node_put,
-    .create = fat_create,
+    .create = fat_create_node,
-    .destroy = fat_destroy,
+    .destroy = fat_destroy_node,
     .link = fat_link,
     .unlink = fat_unlink,
     .index_get = fat_index_get,
     .size_get = fat_size_get,
     .lnkcnt_get = fat_lnkcnt_get,
     .plb_get_char = fat_plb_get_char,
     .is_directory = fat_is_directory,
     .is_file = fat_is_file
 };
+/*
+ * VFS operations.
+ */
+void fat_mounted(ipc_callid_t rid, ipc_call_t *request)
+{
+    dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
+    fat_bs_t *bs;
+    uint16_t bps;
+    uint16_t rde;
+    int rc;
+    /* initialize libblock */
+    rc = block_init(dev_handle, BS_SIZE);
+    if (rc != EOK) {
+        ipc_answer_0(rid, rc);
+        return;
+    }
+    /* prepare the boot block */
+    rc = block_bb_read(dev_handle, BS_BLOCK * BS_SIZE, BS_SIZE);
+    if (rc != EOK) {
+        block_fini(dev_handle);
+        ipc_answer_0(rid, rc);
+        return;
+    }
+    /* get the buffer with the boot sector */
+    bs = block_bb_get(dev_handle);
+    /* Read the number of root directory entries. */
+    bps = uint16_t_le2host(bs->bps);
+    rde = uint16_t_le2host(bs->root_ent_max);
+    if (bps != BS_SIZE) {
+        block_fini(dev_handle);
+        ipc_answer_0(rid, ENOTSUP);
+        return;
+    }
+    /* Initialize the block cache */
+    rc = block_cache_init(dev_handle, bps, 0 /* XXX */);
+    if (rc != EOK) {
+        block_fini(dev_handle);
+        ipc_answer_0(rid, rc);
+        return;
+    }
+    rc = fat_idx_init_by_dev_handle(dev_handle);
+    if (rc != EOK) {
+        block_fini(dev_handle);
+        ipc_answer_0(rid, rc);
+        return;
+    }
+    /* Initialize the root node. */
+    fat_node_t *rootp = (fat_node_t *)malloc(sizeof(fat_node_t));
+    if (!rootp) {
+        block_fini(dev_handle);
+        fat_idx_fini_by_dev_handle(dev_handle);
+        ipc_answer_0(rid, ENOMEM);
+        return;
+    }
+    fat_node_initialize(rootp);
+    fat_idx_t *ridxp = fat_idx_get_by_pos(dev_handle, FAT_CLST_ROOTPAR, 0);
+    if (!ridxp) {
+        block_fini(dev_handle);
+        free(rootp);
+        fat_idx_fini_by_dev_handle(dev_handle);
+        ipc_answer_0(rid, ENOMEM);
+        return;
+    }
+    assert(ridxp->index == 0);
+    /* ridxp->lock held */
+    rootp->type = FAT_DIRECTORY;
+    rootp->firstc = FAT_CLST_ROOT;
+    rootp->refcnt = 1;
+    rootp->lnkcnt = 0;  /* FS root is not linked */
+    rootp->size = rde * sizeof(fat_dentry_t);
+    rootp->idx = ridxp;
+    ridxp->nodep = rootp;
+    futex_up(&ridxp->lock);
+    ipc_answer_3(rid, EOK, ridxp->index, rootp->size, rootp->lnkcnt);
+}
+void fat_mount(ipc_callid_t rid, ipc_call_t *request)
+{
+    ipc_answer_0(rid, ENOTSUP);
+}
 void fat_lookup(ipc_callid_t rid, ipc_call_t *request)
+{
     libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request);
+}
+void fat_read(ipc_callid_t rid, ipc_call_t *request)
+{
+    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
+    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
+    off_t pos = (off_t)IPC_GET_ARG3(*request);
+    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
+    fat_bs_t *bs;
+    uint16_t bps;
+    size_t bytes;
+    block_t *b;
+    if (!nodep) {
+        ipc_answer_0(rid, ENOENT);
+        return;
+    }
+    ipc_callid_t callid;
+    size_t len;
+    if (!ipc_data_read_receive(&callid, &len)) {
+        fat_node_put(nodep);
+        ipc_answer_0(callid, EINVAL);
+        ipc_answer_0(rid, EINVAL);
+        return;
+    }
+    bs = block_bb_get(dev_handle);
+    bps = uint16_t_le2host(bs->bps);
+    if (nodep->type == FAT_FILE) {
+        /*
+         * Our strategy for regular file reads is to read one block at
+         * most and make use of the possibility to return less data than
+         * requested. This keeps the code very simple.
+         */
+        if (pos >= nodep->size) {
+            /* reading beyond the EOF */
+            bytes = 0;
+            (void) ipc_data_read_finalize(callid, NULL, 0);
+        } else {
+            bytes = min(len, bps - pos % bps);
+            bytes = min(bytes, nodep->size - pos);
+            b = fat_block_get(bs, nodep, pos / bps,
+                BLOCK_FLAGS_NONE);
+            (void) ipc_data_read_finalize(callid, b->data + pos % bps,
+                bytes);
+            block_put(b);
+        }
+    } else {
+        unsigned bnum;
+        off_t spos = pos;
+        char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
+        fat_dentry_t *d;
+        assert(nodep->type == FAT_DIRECTORY);
+        assert(nodep->size % bps == 0);
+        assert(bps % sizeof(fat_dentry_t) == 0);
+        /*
+         * Our strategy for readdir() is to use the position pointer as
+         * an index into the array of all dentries. On entry, it points
+         * to the first unread dentry. If we skip any dentries, we bump
+         * the position pointer accordingly.
+         */
+        bnum = (pos * sizeof(fat_dentry_t)) / bps;
+        while (bnum < nodep->size / bps) {
+            off_t o;
+            b = fat_block_get(bs, nodep, bnum, BLOCK_FLAGS_NONE);
+            for (o = pos % (bps / sizeof(fat_dentry_t));
+                o < bps / sizeof(fat_dentry_t);
+                o++, pos++) {
+                d = ((fat_dentry_t *)b->data) + o;
+                switch (fat_classify_dentry(d)) {
+                case FAT_DENTRY_SKIP:
+                case FAT_DENTRY_FREE:
+                    continue;
+                case FAT_DENTRY_LAST:
+                    block_put(b);
+                    goto miss;
+                default:
+                case FAT_DENTRY_VALID:
+                    fat_dentry_name_get(d, name);
+                    block_put(b);
+                    goto hit;
+                }
+            }
+            block_put(b);
+            bnum++;
+        }
+miss:
+        fat_node_put(nodep);
+        ipc_answer_0(callid, ENOENT);
+        ipc_answer_1(rid, ENOENT, 0);
+        return;
+hit:
+        (void) ipc_data_read_finalize(callid, name, strlen(name) + 1);
+        bytes = (pos - spos) + 1;
+    }
+    fat_node_put(nodep);
+    ipc_answer_1(rid, EOK, (ipcarg_t)bytes);
+}
+void fat_write(ipc_callid_t rid, ipc_call_t *request)
+{
+    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
+    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
+    off_t pos = (off_t)IPC_GET_ARG3(*request);
+    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
+    fat_bs_t *bs;
+    size_t bytes;
+    block_t *b;
+    uint16_t bps;
+    unsigned spc;
+    unsigned bpc;       /* bytes per cluster */
+    off_t boundary;
+    int flags = BLOCK_FLAGS_NONE;
+    if (!nodep) {
+        ipc_answer_0(rid, ENOENT);
+        return;
+    }
+    ipc_callid_t callid;
+    size_t len;
+    if (!ipc_data_write_receive(&callid, &len)) {
+        fat_node_put(nodep);
+        ipc_answer_0(callid, EINVAL);
+        ipc_answer_0(rid, EINVAL);
+        return;
+    }
+    bs = block_bb_get(dev_handle);
+    bps = uint16_t_le2host(bs->bps);
+    spc = bs->spc;
+    bpc = bps * spc;
+    /*
+     * In all scenarios, we will attempt to write out only one block worth
+     * of data at maximum. There might be some more efficient approaches,
+     * but this one greatly simplifies fat_write(). Note that we can afford
+     * to do this because the client must be ready to handle the return
+     * value signalizing a smaller number of bytes written.
+     */
+    bytes = min(len, bps - pos % bps);
+    if (bytes == bps)
+        flags |= BLOCK_FLAGS_NOREAD;
+    boundary = ROUND_UP(nodep->size, bpc);
+    if (pos < boundary) {
+        /*
+         * This is the easier case - we are either overwriting already
+         * existing contents or writing behind the EOF, but still within
+         * the limits of the last cluster. The node size may grow to the
+         * next block size boundary.
+         */
+        fat_fill_gap(bs, nodep, FAT_CLST_RES0, pos);
+        b = fat_block_get(bs, nodep, pos / bps, flags);
+        (void) ipc_data_write_finalize(callid, b->data + pos % bps,
+            bytes);
+        b->dirty = true;        /* need to sync block */
+        block_put(b);
+        if (pos + bytes > nodep->size) {
+            nodep->size = pos + bytes;
+            nodep->dirty = true;    /* need to sync node */
+        }
+        ipc_answer_2(rid, EOK, bytes, nodep->size);
+        fat_node_put(nodep);
+        return;
+    } else {
+        /*
+         * This is the more difficult case. We must allocate new
+         * clusters for the node and zero them out.
+         */
+        int status;
+        unsigned nclsts;
+        fat_cluster_t mcl, lcl;
+        nclsts = (ROUND_UP(pos + bytes, bpc) - boundary) / bpc;
+        /* create an independent chain of nclsts clusters in all FATs */
+        status = fat_alloc_clusters(bs, dev_handle, nclsts, &mcl, &lcl);
+        if (status != EOK) {
+            /* could not allocate a chain of nclsts clusters */
+            fat_node_put(nodep);
+            ipc_answer_0(callid, status);
+            ipc_answer_0(rid, status);
+            return;
+        }
+        /* zero fill any gaps */
+        fat_fill_gap(bs, nodep, mcl, pos);
+        b = _fat_block_get(bs, dev_handle, lcl, (pos / bps) % spc,
+            flags);
+        (void) ipc_data_write_finalize(callid, b->data + pos % bps,
+            bytes);
+        b->dirty = true;        /* need to sync block */
+        block_put(b);
+        /*
+         * Append the cluster chain starting in mcl to the end of the
+         * node's cluster chain.
+         */
+        fat_append_clusters(bs, nodep, mcl);
+        nodep->size = pos + bytes;
+        nodep->dirty = true;        /* need to sync node */
+        ipc_answer_2(rid, EOK, bytes, nodep->size);
+        fat_node_put(nodep);
+        return;
+    }
+}
+void fat_truncate(ipc_callid_t rid, ipc_call_t *request)
+{
+    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
+    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
+    size_t size = (off_t)IPC_GET_ARG3(*request);
+    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
+    fat_bs_t *bs;
+    uint16_t bps;
+    uint8_t spc;
+    unsigned bpc;   /* bytes per cluster */
+    int rc;
+    if (!nodep) {
+        ipc_answer_0(rid, ENOENT);
+        return;
+    }
+    bs = block_bb_get(dev_handle);
+    bps = uint16_t_le2host(bs->bps);
+    spc = bs->spc;
+    bpc = bps * spc;
+    if (nodep->size == size) {
+        rc = EOK;
+    } else if (nodep->size < size) {
+        /*
+         * The standard says we have the freedom to grow the node.
+         * For now, we simply return an error.
+         */
+        rc = EINVAL;
+    } else if (ROUND_UP(nodep->size, bpc) == ROUND_UP(size, bpc)) {
+        /*
+         * The node will be shrunk, but no clusters will be deallocated.
+         */
+        nodep->size = size;
+        nodep->dirty = true;        /* need to sync node */
+        rc = EOK;
+    } else {
+        /*
+         * The node will be shrunk, clusters will be deallocated.
+         */
+        if (size == 0) {
+            fat_chop_clusters(bs, nodep, FAT_CLST_RES0);
+        } else {
+            fat_cluster_t lastc;
+            (void) fat_cluster_walk(bs, dev_handle, nodep->firstc,
+                &lastc, (size - 1) / bpc);
+            fat_chop_clusters(bs, nodep, lastc);
+        }
+        nodep->size = size;
+        nodep->dirty = true;        /* need to sync node */
+        rc = EOK;
+    }
+    fat_node_put(nodep);
+    ipc_answer_0(rid, rc);
+    return;
+}
+void fat_destroy(ipc_callid_t rid, ipc_call_t *request)
+{
+    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
+    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
+    int rc;
+    fat_node_t *nodep = fat_node_get(dev_handle, index);
+    if (!nodep) {
+        ipc_answer_0(rid, ENOENT);
+        return;
+    }
+    rc = fat_destroy_node(nodep);
+    ipc_answer_0(rid, rc);
+}
 /**
  * @}
  */

Subversion Repositories HelenOS

(root)/branches/dd/uspace/srv/fs/fat/fat_ops.c – Rev 3022 → 4055